Particle migration behavior of fractured lost circulation control: Numerical simulation

Abstract

Fracture loss is the most common type of leakage in petroleum drilling engineering. The existing numerical simulation of the particle transport process is relatively simplified. In order to clarify the dynamic behavior characteristics of bridging particles in fractures, this paper adopts the discrete element and computational fluid dynamics coupling numerical simulation methods to establish a bidirectional coupling numerical model of bridging particles and drilling fluid to simulate the dynamic evolution process of bridging plugging particles, such as migration, bridging, and accumulation. The results show that the main factors affecting the transport pattern of plugging particles in the fracture are differential pressure, particle size, drilling fluid viscosity, drilling fluid density, fracture width, and fracture length. The drilling fluid density has a small effect on the inter-particle force in the fracture; the drilling fluid viscosity mainly affects the resistance of the particles, and the pressure difference between the inlet and outlet of the fracture mainly affects the transport speed of the particles. The particle size determines whether a plugging layer can be formed, and the best plugging effect is achieved when the particle size is 1/2 of the fracture width.

Study on the Behavior and State of Viscous Fractured Leakage Bridging and Plugging Slurry during the Pump-In and Pressurization Process

“…Most researchers have focused on the settling behavior of solid particles in conventional plugging slurry systems, while there is limited research on the dynamic settling behavior of sealing particles in plugging mud under fracturing and wellbore conditions. The dynamic settling process of particles in plugging slurry is a complex dynamic behavior [10], and at present, the understanding primarily relies on experimental methods to explain the phenomena and mechanisms of particle settling, with limited studies utilizing numerical simulation methods. Based on previous research, the behavior and flow process of suspended particles and settlement characteristics during the pumping and lifting of plugging slurry into formations and the subsequent pumping of plugging slurry are still not well understood, leading to significant uncertainties in subsequent operational processes.…”